Those comments came from people who did not realize this game was a remake of a previous demo/alpha called Salvor Deep. And so they harshly attacked the game despite knowing nothing of the situation.
I'm not out to witchhunt anyone or anything but I do think it is kinda understandable. The original game isn't some kind of abandoned proof of concept; it's, to the original dev, complete (1.0.0), fairly recent, apparently maintained, buyable, and playable product on Steam and Itchio. If that's not a complete game, then I don't know what is.
https://f95zone.to/threads/hi-everyone.266145/post-18206472
Considering this dev themselves said the project originally started as free fan remake/expansion before going paid, and the extensive similarities, I think that being a kneejerk reaction is fairly reasonable. I didn't get to see all of the responses to it, but of course this doesn't excuse harassment or personal attacks but concerns about it is expected.
BUT I mean, so much could've been mitigated by just, acknowledging the former game? The original thread has no mention of it, just a lil "Inspired by Salvor DEEP" would have gotten ahead of 90% of it. Apparently the two devs had a spot of drama at some spot? But that's resolved and I don't think the original dev ever rescinded support. Should people have been as pissy about it as some people are saying they were? No, certainly not. But it wouldn't have taken a lot of work to just clear the air.